In any enclosed system containing a flowing fluid, such as a piping system, there is frequently a need to make directional changes in the fluid flow. Typically, standard piping elbows, also referred to as bends, are used. However, circumstances frequently exist that impose constraints and preclude the use of standard piping elbows. These circumstances include the conveying of high temperature fluids, corrosive fluid streams, or abrasive fluid streams such as those that are particulate-laden fluid streams. When these conditions exist, a typical solution to changing the fluid flow direction often involves using larger size (that is, greater diameter) piping elements lined with an appropriate refractory, corrosion-resistant, or abrasion-resistant lining.
An increase in the piping diameter requires an accompanying increase in the turning radius of any needed bends. The increase in turning radius in turn increases the space requirements for installing an elbow or bend needed to make a change in the fluid flow direction. Utilizing an elbow or bend with too small of a turning radius typically causes an undesirable pressure loss.
As related in a commonly-assigned application filed concurrently with the present application, the inventors have addressed these deficiencies by providing a piping elbow capable of facilitating a fluid flow direction change in a smaller space than conventional piping elbows, without causing the larger pressure losses found when using conventional elbows in the equivalent space. These piping elbows comprise a substantially-cylindrical body having a first end, a second end, and a substantially-constant inside diameter; a tangential inlet attached to the body near the first end of the body and having an inside diameter smaller than the inside diameter of the body; and a tangential outlet attached to the body near the second end of the body and having an inside diameter smaller than the inside diameter of the body. Typically, fluid flows linearly through the tangential inlet and enters the body. Inside the body, linear motion of the fluid is converted into a rotational or spiral motion. The fluid in the body continues its spiral motion as it also moves axially through the body toward the tangential outlet. The fluid exits the body through the tangential outlet. Upon exiting through the tangential outlet, rotational or spiral motion of the fluid in the body is converted back into linear motion.
In a preferred embodiment, the piping elbows comprise two substantially-identical components attached to each other. In another preferred embodiment, the two substantially-identical components are removably attached to each other so that the tangential inlet/outlet on the first component can be oriented at any desired angle with respect to the tangential inlet/outlet on the second component.
Together with the development of the described piping elbows, and as related in a further commonly-assigned application filed concurrent with the present application, the inventors have additionally conceived a liner for use with the piping elbows. In one embodiment, the liner comprises a body liner, a tangential inlet liner, and a tangential outlet liner. In a preferred embodiment, the tangential inlet liner and the tangential outlet liner are each removably inserted into a cavity in the body liner. In another embodiment, the body section liner comprises two substantially-identical body section liners.
The present application, in a preferred embodiment, concerns methods and apparatus for detecting wear in such liners, though it will be appreciated that the inventive methods and apparatus are more broadly applicable to the whole of lined vessels generally (and “vessels” here should be taken as referring to any structure in or through which a fluid, especially an abrasive fluid, moves). In one embodiment, an electrically conductive wire is placed on or near the outside surface of the liner (relative to the fluid flow) and the electrical resistance in the electrically conductive wire is measured to determine whether the wire has worn through. In another embodiment, the temperature measured by a temperature measuring device, such as a thermocouple, is monitored over time to estimate wear in the liner.